Lower fan leaves turning yellow and brown! Please help

My plant is 2 1/2 weeks old is a Nirvana short rider auto flower. The lower fan leaves are starting to turn yellow and brown.

I am growing in Fox farms Ocean Forest with a 250W HPS about 18 inches above the plant (the light has an open hood just a cheap bat wing) with two small 26W CFL's with a 4 inch Value Line in-line fan for an exhaust. I have not been adding fertilizer until last night I added quarter strength. PH level is fine!
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I cant see your pics for some reason. But mine are doing the same thing, well just one.

https://www.rollitup.org/dwc-bubbleponics/248131-my-first-dwc-grow-w-7.html#post3227732

I have it in dwc, but I am using all fox farm nutes. I also have one in ffof but it is a runt.

I think ffof is pretty dam strong as it is. I mean you shouldnt have to add any nutes up untill your flowering stage. However thise varies from strain to strain. Whats the avg temp you running?

was it yellowing before you hit it with ferts or only after?

no i dont remember actually i say after ferts, but I have two that are doing great! and this one is not... which is strange, cause its the one that has the most roots.